JP2010222618A - Cu-Ni-Si-based copper alloy rolled plate and electrical parts using the same - Google Patents

Abstract

A Cu-Ni-Si-based copper alloy rolled sheet excellent in press workability, bending workability and strength is provided.
A copper alloy rolled sheet containing 1.0 to 4.0% by mass of Ni and 0.1 to 0.8% by mass of Si, the balance being Cu and unavoidable impurities, and X-ray diffraction When measuring the crystal orientation from the plate surface to a depth of 5 μm by the method, α = 0 ± 10 ° on the {111} positive pole figure (where α is perpendicular to the rotational axis of the diffraction goniometer specified in the Schulz method) This is a Cu—Ni—Si based copper alloy rolled sheet having a pole texture of a shear texture corresponding to a region of (axis) of 2 or more and 8 or less.
[Selection] Figure 1

Description

  The present invention relates to a copper alloy that is excellent in strength and conductivity, and can be suitably applied to, for example, a spring material for electronic equipment.

  Spring materials (connector materials) for electrical and electronic equipment such as terminals, connectors, switches, and relays are required to have excellent spring characteristics, bending workability, and conductivity, and phosphor bronze has been conventionally used. However, in recent years, precipitation-strengthening-type copper alloys such as Corson alloy, beryllium copper, and titanium copper have been developed in place of conventional solid solution-strengthening-type copper alloys such as phosphor bronze and brass because of the demand for further miniaturization of electronic components. .

Such terminals, connectors, and the like are formed into a desired shape from a copper alloy material by pressing, but with the miniaturization of electronic components, dimensional accuracy after punching has become important.
As a technique for improving the press workability of the above-described copper alloy for electronic devices, a technique for covering a Cu layer on the surface of the copper alloy is disclosed (see Patent Document 1). Moreover, the technique which improves press workability by restrict | limiting the orientation of the texture of a copper alloy is proposed (refer patent documents 2-4).
In particular, the suppression of sagging and burrs, which is a problem in press processing, has been addressed by adjusting the mold, but as the dimensional accuracy of electronic parts is required to improve, the sagging is small and the burrs are low. Is required.

JP 2006-272889 A JP 2007-186799 A Japanese Patent No. 3800209 Japanese Patent No. 4009981

By the way, normally, in the cold rolling, crystal lattice rotation proceeds with the plastic deformation of the material, and a texture is formed. However, in the surface layer region of the material in contact with the roll at the time of rolling, a texture different from the material center is formed. It is known to form. This is because the material is deformed by the compressive stress in the plate thickness direction and the tensile stress in the rolling direction at the center of the material, and a so-called rolling texture is formed. This is because the material is subjected to shear deformation under the influence of the above, and a surface texture (shear texture) is formed.
As a result of studies by the present inventors, it has been found that, in a copper alloy rolled plate, press workability is greatly improved by increasing the extreme density of the shear texture from the plate surface to a depth of 5 μm.
However, in the case of a conventional rolled copper alloy sheet, the portion where the extreme density of the shear texture is high is limited to the extreme surface of the sheet, and the press workability is not sufficient.
FIG. 1 schematically shows the extreme density of the shear texture of the rolled copper alloy sheet of the present invention and the conventional rolled copper alloy sheet. Also in conventional copper alloy rolling, the pole density of the shear texture on the pole surface of the plate is 2 or more, but the pole density rapidly decreases as it goes inside, and the pole density is 2 at a depth of 5 μm from the plate surface. Has become less.

  As described above, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a Cu-Ni-Si-based copper alloy rolled plate excellent in press workability, bending workability and strength. .

  The rolled Cu-Ni-Si copper alloy sheet of the present invention contains 1.0 to 4.0% by mass of Ni and 0.1 to 0.8% by mass of Si, with the balance being Cu and inevitable impurities. It is a rolled copper alloy plate, and when the crystal orientation from the plate surface to a depth of 5 μm is measured by the X-ray diffraction method, α = 0 ± 10 ° on the {111} positive pole figure (where α is a Schulz method) The polar density of the shear texture corresponding to the region of the axis of rotation defined by the diffraction goniometer is 2 to 8.

Furthermore, it is preferable to contain 0.05-2.0 mass% in total of 1 or more types chosen from the group of Mg, Sn, Zn, and Mn.
Furthermore, it is preferable to contain 1.0 to 1.5% by mass of Co and 0.05 to 0.2% by mass of Cr.
The ten-point average roughness of the plate surface is preferably 0.4 to 1.2 μm.

  The electrical component of the present invention uses the Cu-Ni-Si-based copper alloy rolled plate.

  According to the present invention, it is possible to obtain a Cu—Ni—Si based copper alloy rolled sheet excellent in press workability, bending workability and strength.

  Hereinafter, embodiments of the rolled Cu—Ni—Si copper alloy sheet according to the present invention will be described. In the present invention,% means mass% (% by weight) unless otherwise specified.

(composition)
[Ni and Si]
The concentration of Ni in the copper alloy rolled sheet is set to 1.0 to 4.0%, and the concentration of Si is set to 0.1 to 0.8%. Ni and Si are dissolved at the time of dissolution of the copper alloy, and heat treatment is performed after the solution treatment to cause aging precipitation, thereby forming fine particles of an intermetallic compound mainly containing Ni ₂ Si. As a result, the strength of the copper alloy is remarkably increased and the electrical conductivity is also increased.
If the Ni concentration is less than 1.0%, sufficient strength of the copper alloy cannot be obtained, and if it exceeds 4.0%, cracking occurs during hot rolling. If the Si concentration is less than 0.1%, sufficient strength of the copper alloy cannot be obtained, and if it exceeds 0.8%, the conductivity is lowered.

[Mg, Sn, Zn and Mn]
The copper alloy rolled sheet may further contain 0.05 to 2.0% in total of one or more selected from the group consisting of Mg, Sn, Zn and Mn.
If the total of these elements is less than 0.05%, the effect of improving the characteristics of the copper alloy such as stress relaxation characteristics, hot workability, strength, and heat resistance shown below cannot be obtained, and if it exceeds 2.0% Conductivity may be reduced.
Here, Mg has the effect of improving the stress relaxation characteristics and hot workability of the copper alloy, but the effect cannot be obtained if it is less than 0.05%, and if it exceeds 0.2%, the castability (casting surface quality) ), Hot workability, and plating heat-resistant peelability may be lowered, so the Mg concentration is preferably 0.05 to 0.2%.
Sn and Zn have the effect of improving the strength and heat resistance of the copper alloy, Sn further improves the stress relaxation resistance of the copper alloy, and Zn improves the heat release resistance of the copper alloy during Sn plating. The concentration of Sn is preferably 0.2 to 1%, and the concentration of Zn is preferably 0.2 to 1%. If the concentration of Sn or Zn is less than 0.2%, the above effect cannot be obtained, and if it exceeds 1%, the conductivity decreases.
Mn has the effect of improving hot workability in addition to the effect of improving strength by solid solution strengthening. If Mn is less than 0.05%, the above effect cannot be obtained, and if it exceeds 0.15%, the conductivity decreases. Therefore, the Mn concentration is preferably 0.05 to 0.15%.

[Co, Cr]
The copper alloy rolled plate may further contain 1.0 to 1.5 mass% Co and 0.05 to 0.2 mass% Cr. Co forms an intermetallic compound with Si and has the effect of improving strength by precipitation strengthening. If Co is less than 1.0%, the above effect cannot be obtained, and if it exceeds 1.5%, the conductivity is lowered and the cost is also increased. Cr has the effect of improving hot workability. If Cr is less than 0.05%, the above effect cannot be obtained, and if it exceeds 0.2%, the conductivity is lowered.

(Extreme density of shear texture)
Usually, in cold rolling, the crystal lattice rotation proceeds with the plastic deformation of the material and a texture is formed, but there is a difference in the texture formed in the surface layer region of the material in contact with the roll during rolling and in the center of the material. (Jojo et al., Journal of the Japan Institute of Metals, p33, 36, 1972, edited by Isao Gokyu, “Advances in Metal Plastic Processing”, p499, Corona, 1978). This is because the material is deformed by the biaxial stress that combines the compressive stress in the plate thickness direction and the tensile stress in the rolling direction at the center of the material, whereas the frictional force with the roll is at the material surface layer. This is because the material undergoes shear deformation due to the influence, which is called a surface texture (shear texture) and is distinguished from a rolling texture. For example, it has been found that in an Al plate, a surface texture is formed on both sides of the plate by 30% of the plate thickness under optimum conditions, and the inner structure is rapidly changed by a thin transition layer. As a result of investigations by the present inventors, it has been clarified that, in a copper alloy rolled sheet, the surface texture can be formed about 10 to 20% with respect to the sheet thickness by controlling the manufacturing conditions. As a result of further investigation, it was found that the press workability is changed by controlling the surface texture (shear texture) in the rolled copper alloy sheet.

In the present invention, when the crystal orientation from the plate surface to a depth of 5 μm is measured by the X-ray diffraction method, α = 0 ± 10 ° on the {111} positive pole figure (where α: for diffraction specified in the Schulz method) The pole density of the shear texture corresponding to the region of the axis perpendicular to the rotation axis of the goniometer is defined as 2 or more and 8 or less.
Here, the reason for the depth from the plate surface to a depth of 5 μm is that when the relationship between the surface texture and the press workability was investigated using the Cu—Ni—Si based copper alloy rolled plate of the present invention, it was 5 μm or more. Since a significant difference occurred in press workability when the surface texture was formed, this depth was used as the measurement target.

As described above, the extreme density of the shear texture is measured. When a rolled plate having a shear texture with an extreme density of 2 or more and 8 or less is punched and pressed, the sag of the material generated after press punching is smaller than that of the conventional material, and the burr is lower than that of the conventional material. There was found.
When the extreme density of the shear texture having a depth of 5 μm from the plate surface is less than 2, the shear texture is not sufficiently formed, the sag increases and the burr increases, and the press workability is not improved. On the other hand, it is industrially difficult for the polar density of the shear texture to exceed 8, and the upper limit of the polar density is set to 8. When the extreme density is in the range of 2 to 3, the press workability improves as the extreme density of the shear texture increases (the sagging is small and the burr becomes low). The degree of improvement in workability slows down, and when the pole density exceeds 5, no difference is seen in press workability. Further, in order to obtain a high pole density exceeding 5, it is necessary to use a rolling oil having a high viscosity and to increase the rolling speed, and the surface roughness of the material increases. On the other hand, when the pole density exceeds 4.5, wrinkles are generated in the bent portion processed portion. Therefore, the pole density is preferably 2.2 or more and 5 or less, and more preferably 2.5 or more and 4.5 or less.
In the case of a conventional rolled copper alloy plate, the portion having a high extreme density of the shear texture is limited to the extreme surface of the plate, so that press workability is not sufficient. FIG. 1 schematically shows the extreme density of the shear texture of the rolled copper alloy sheet of the present invention and a conventional rolled copper alloy sheet. Also in conventional copper alloy rolling, the pole density of the shear texture on the pole surface of the plate is 2 or more, but the pole density rapidly decreases as it goes inside, and the pole density is 2 at a depth of 5 μm from the plate surface. Has become less.

As a method for controlling the extreme density of the shear texture from the plate surface to a depth of 5 μm to 2 or more and 8 or less, there is a method for increasing the frictional force between the roll and the copper alloy rolled material at the time of final cold rolling. It is done. Specifically, at the time of final cold rolling, 1) increase the viscosity of the rolling oil, 2) increase the roughness of the rolling roll, and 3) increase the rolling speed (reducing the roll diameter). It is done.
Usually, the viscosity of the rolling oil at the time of cold rolling is about 0.03 to 0.06 cm ² / s, and the viscosity of the rolling oil at the time of the final cold rolling is set to 0.06 cm ² / s or more, thereby shearing The extreme density of the texture can be 2 or more and 8 or less.
In addition, although the copper alloy rolled sheet of this invention heat-processes Ni and Si which carried out solid solution, and age-precipitates, any may be sufficient as the order of an aging treatment and the said last cold rolling.

  In the rolled copper alloy sheet of the present invention, the 10-point average roughness of the sheet surface is preferably 0.4 to 1.2 μm. If the 10-point average roughness of the plate surface is less than 0.4 μm, the lubricating oil may not be sufficiently supplied between the mold and the material during pressing, and the fracture surface ratio and burrs may increase. Further, when a copper alloy rolled sheet is produced by a normal method, the ten-point average roughness of the sheet surface does not exceed 1.2 μm.

(Production method)
The manufacturing process of the copper alloy rolled sheet of the present invention is as follows. First, electrolytic copper or oxygen-free copper is used as a main raw material, and the composition to which the above chemical components and others are added is dissolved in the atmosphere under charcoal coating to produce an ingot. After the ingot is hot-rolled, heat treatment and cold rolling are repeated to produce a desired strip or foil. The heat treatment includes a solution treatment and an aging treatment. In the solution treatment, the material is heated in a high temperature range of 700 to 1000 ° C., and the constituent elements (Ni · Si and subcomponents) of the precipitate are dissolved in the matrix. Thereafter, an aging treatment is performed in a temperature range of 300 to 600 ° C. to precipitate a fine compound from the parent phase and improve the strength. In order to obtain higher strength before or after aging, cold rolling may be performed. In addition, strain relief annealing may be performed after cold rolling.

  The rolled copper alloy sheet of the present invention can be in various forms such as spring materials (strips) and foils. For example, when the copper alloy of the present invention is used as a strip for a spring material, it can be applied to electrical parts such as lead frames, connectors, pins, terminals, relays, and switches. The connector can be applied to all known forms and structures, but usually consists of a male (jack, plug) and a female (socket, receptacle). For example, the terminals may be arranged like a spring, with a number of skewered pins arranged side by side and appropriately bent so that the terminals come into electrical contact with each other when fitted to other connectors. And the terminal of a connector is normally comprised with the copper alloy rolled sheet of this invention.

  EXAMPLES Next, although an Example is given and this invention is demonstrated further in detail, this invention is not limited to these.

<Example 1>
1. Preparation of Sample Ni 1.6%, Si 0.4%, Sn 0.4%, and Zn 0.5% were added to electrolytic copper, respectively, and dissolved in an atmospheric melting furnace covered with charcoal, and the molten metal was stirred. Thereafter, an ingot was cast at a casting temperature of 1250 ° C., and this was annealed at 900 ° C. for 3 hours, and then hot-rolled to a thickness of 11 mm. After removing the oxide scale on the surface layer of the hot-rolled material by chamfering, it is cold-rolled to a sheet thickness of 0.24 mm, further subjected to a solution treatment at a solution temperature shown in Table 1 for 1 minute, and a rolled plate sample Got. Next, after an aging treatment was performed at 450 ° C. for 10 hours, final cold rolling was performed to 0.2 mm. The rolling density at the time of final cold rolling and the viscosity of the rolling oil were changed as shown in Table 1 to adjust the extreme density of the shear texture.

2. Measurement of polar density of shear texture Using an X-ray diffractometer (RINT2500, manufactured by Rigaku Corporation), {111} positive electrode points of each sample were measured by a reflection method to produce {111} positive electrode dot diagrams. However, in the reflection method, measurement becomes difficult when the incident angle of the X-ray with respect to the sample surface becomes shallow. Therefore, the angle ranges that can be actually measured are 0 ° ≦ α ≦ 75 ° and 0 ° ≦ β ≦ 360 on the positive electrode diagram. ° (where α is an axis perpendicular to the rotational axis of the diffraction goniometer defined in the Schulz method, β is an axis parallel to the rotational axis).
In the measurement, the X-ray intensity at 16 × 73 = 1168 points was measured by scanning the angle range described above with α and β rotation intervals Δα and Δβ set to 5 °. At this time, the strength of the texture on the positive point diagram was normalized by assuming that the texture has no texture (that is, the crystal orientation is random) as 1. Assuming that the crystal orientation was random, {111} positive electrode point measurement of a copper powder sample was performed, and this was set to 1.
As the X-ray irradiation conditions, a Co tube was used, the tube voltage was set to 30 kV, the tube current was set to 100 mA, and the conditions were set so that the X-ray penetrated to a depth of 5 μm from the plate surface.
As described above, the polar density of the crystal orientation in the range of α = 0 ° ± 10 ° on the {111} positive electrode diagram corresponding to the shear texture is measured, and the maximum value of the polar density in this range is It was defined as the extreme density of the shear texture.

3. Size of Sagging For each sample, a die clearance was set to 10%, a lead having a length of 30 mm and a width of 0.5 mm was punched at a punching speed of 250 spm, and a cross section of the punched material was photographed with a confocal microscope. Of the photographed image, the highest part on the punching start surface side (the part far from the punching position in the center of the punching material) and the lowest part (the punching position, where the material sags down The difference in altitude from that of the part) was defined as the size of the sagging.
When the size of the sagging was within 30 μm, it was judged that the sagging was small and good.

4). Burr Height For each sample, a die clearance was set to 10%, a lead having a length of 30 mm and a width of 0.5 mm was punched at a punching speed of 250 spm, and a cross section of the punched material was photographed with a confocal microscope. In the photographed image, the height difference between the highest part on the punching end surface side and the lowest part was defined as the burr height.
If the burr height was within 10 μm, the burr was judged to be low and good.

5). Bending workability According to the Japan Copper and Brass Association (JBMA) technical standard T307 (1999), a bending test was performed such that the bending radius was 0.1 mm and the bending axis was parallel to the rolling direction. Corresponding to the five grades A to E of the technical standard, the following criteria were used.
○: A (good) of the technical standard △: B (small wrinkle) and C (large wrinkle) of the technical standard
×: D (small crack) and E (large crack) of the same technical standard

6). Tensile strength Each sample was subjected to a tensile test in accordance with JISZ2241 in a direction parallel to the rolling direction to determine the tensile strength. If the tensile strength is 650 MPa or more, the spring material is good.

  The obtained results are shown in Table 1.

As is clear from Table 1, in the case of Invention Examples 1 to 11, the sagging was small and the burrs were low, the press workability was excellent, and the bending workability was also good. Furthermore, the tensile strength was also high.
On the other hand, in the case of Comparative Example 1, Comparative Example 3 and Comparative Example 5 in which the rolling speed at the time of the final cold rolling is less than 160 mpm, the extreme density of the shear texture becomes less than 2, the sagging is large, the burr is high, and the press workability Deteriorated.
In Comparative Examples 2 and 6, the viscosity of the rolling oil was as low as 0.03 cm ² / s or less, the extreme density of the shear texture was less than 2, the sagging was large, the burr was high, and the press workability was deteriorated.
In the case of Comparative Example 4, the solution temperature was as low as 700 ° C., the extreme density of the shear texture was less than 2, the sagging was large and the burr was high, and the press workability was deteriorated. This is because, since the solution temperature is low, recrystallization does not occur during the solution treatment, and a desired shear texture cannot be obtained due to the influence of the rolling texture formed before the solution treatment. In addition, the range of the appropriate solution treatment temperature varies depending on the composition of the copper alloy rolled sheet, and is not limited to the temperature range of 760 to 830 ° C. applied to the invention examples.

<Example 2>
Ni, Si, Mg, Sn, Zn, Co, and Cr were added to electrolytic copper in the proportions shown in Table 2, respectively, and dissolved in an atmospheric melting furnace, and the molten metal was stirred. Thereafter, an ingot was cast at a casting temperature of 1250 ° C., annealed at a temperature of 900 ° C. for 3 hours, and then hot-rolled to a plate thickness of 11 mm. After removing the oxide scale on the surface layer of the hot-rolled material by chamfering, it is cold-rolled to a sheet thickness of 0.24 mm, further subjected to a solution treatment for 1 minute at the solution temperature shown in Table 3, and a rolled plate sample is obtained. Obtained. Next, after aging treatment was performed at 450 ° C. for 10 hours, final cold rolling was performed to 0.2 mm. The rolling speed at the time of final cold rolling and the viscosity of the rolling oil were the values shown in Table 3. Each sample was evaluated in exactly the same manner as in Example 1 except for the tensile strength. About tensile strength, since it received to the influence of a composition greatly, 600 MPa or more was determined to be strong. The components of each sample and the results obtained are shown in Table 2 and Table 3, respectively.

As apparent from Table 3, all of the samples of Invention Examples 12 to 23 were small in sagging and low in burrs, excellent in press workability, and good in bending workability. Furthermore, the tensile strength was also good.
In the case of Comparative Example 7 where Ni is less than 1.0% by mass, the press workability was good, but the strength was lowered. In the case of Comparative Example 8 in which Ni exceeded 4.0% by mass and Si exceeded 0.8% by mass, cracking occurred during hot rolling, and sample preparation was not possible.

It is a schematic diagram which shows the extreme density of the shear texture of the copper alloy rolled sheet of this invention and the conventional copper alloy rolled sheet.

Claims (5)

A copper alloy rolled plate containing 1.0 to 4.0% by mass of Ni and 0.1 to 0.8% by mass of Si, with the balance being Cu and inevitable impurities, and the surface of the plate by X-ray diffraction When the crystal orientation from 1 to 5 μm is measured, the region of α = 0 ± 10 ° (where α is the axis perpendicular to the rotational axis of the diffraction goniometer specified in the Schulz method) on the {111} positive pole figure A Cu—Ni—Si based copper alloy rolled sheet having a shear texture with an extreme density of 2 or more and 8 or less. Furthermore, the Cu-Ni-Si type copper alloy rolled sheet of Claim 1 which contains 0.05-2.0 mass% of 1 or more types chosen from the group of Mg, Sn, Zn, and Mn in total. Furthermore, the Cu-Ni-Si type copper alloy rolled sheet of Claim 1 or 2 containing 1.0-1.5 mass% of Co and 0.05-0.2 mass% of Cr. The Cu-Ni-Si copper alloy rolled sheet according to any one of claims 1 to 3, wherein the ten-point average roughness of the sheet surface is 0.4 to 1.2 m. The electrical component using the Cu-Ni-Si type copper alloy rolled sheet in any one of Claims 1-4.

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